Add PBM (portable bitmap) demo

demo_pbm.py

@@ -0,0 +1,108 @@
+"""ILI9341 demo (PBM - Portable Bitmap)."""
+from ili9341 import Display, color565
+from struct import pack, unpack
+from framebuf import FrameBuffer, MONO_HLSB, RGB565  # type: ignore
+from machine import Pin, SPI  # type: ignore
+from time import sleep
+
+
+def create_palette(foreground, background=0, invert=False):
+    """Create framebuffer palette to translate between MONO_HLSB and RGB565.
+
+    Args:
+        foreground(int): Foreground color in RGB656 format
+        background(int): Background color in RGB656 format (default Black)
+        invert(bool): Invert foreground and background (default False)
+    Returns:
+        FrameBuffer: Color palette
+    """
+    # Need to swap endian colors
+    foreground = unpack('>H', pack('<H', foreground))[0]
+    background = unpack('>H', pack('<H', background))[0]
+
+    # Buffer size equals 2 pixels (MONO_HLSB) x 2 byte color depth (RGB565)
+    buffer_size = 4
+    # Define framebuffer
+    palette = FrameBuffer(bytearray(buffer_size), 2, 1, RGB565)
+    # Set foreground & background color pixels (swap if inverted)
+    palette.pixel(0 if invert else 1, 0, background)
+    palette.pixel(1 if invert else 0, 0, foreground)
+    return palette
+
+
+def load_pbm(filename):
+    """Load portable bitmap file.
+
+    Args:
+        filename(str): Path to bitmap
+    Returns:
+        tuple: A tuple containing the following:
+            - FrameBuffer: The image data in MONO_HLSB format.
+            - int: The width of the image.
+            - int: The height of the image.
+    """
+    with open(filename, 'rb') as f:
+        # Read and discard the first 2 lines
+        for _ in range(2):
+            f.readline()
+        # Read dimensions from the third line
+        dimensions = f.readline().split()
+        width = int(dimensions[0])
+        height = int(dimensions[1])
+
+        # Read the bitmap data
+        data = bytearray(f.read())
+    return FrameBuffer(data, width, height, MONO_HLSB), width, height
+
+
+def test():
+    """Test code."""
+    # Baud rate of 40000000 seems about the max
+    spi = SPI(1, baudrate=40000000, sck=Pin(14), mosi=Pin(13))
+    display = Display(spi, dc=Pin(4), cs=Pin(16), rst=Pin(17))
+    display.clear()
+
+    # Load invader .PBM image to framebuffer and get dimensions
+    invader_fb, w, h = load_pbm('images/invaders48x36.pbm')
+
+    # Create RGB565 placeholder
+    placeholder = bytearray(w * h * 2)
+    # Create frame buffer for placeholder
+    placeholder_fb = FrameBuffer(placeholder, w, h, RGB565)
+    # Draw invaders in different color palettes
+    for parameter in [
+        (color565(255, 0, 0), 0, False, 0, 0),
+        (color565(0, 255, 0), 0, False, 0, 54),
+        (color565(0, 0, 255), 0, False, 0, 108),
+        (color565(0, 255, 255), 0, False, 0, 162),
+        (color565(255, 255, 0), 0, False, 0, 216),
+        (color565(255, 0, 255), 0, False, 0, 270),
+        (color565(255, 0, 0), 0, True, 64, 0),
+        (color565(0, 255, 0), 0, True, 64, 54),
+        (color565(0, 0, 255), 0, True, 64, 108),
+        (color565(0, 255, 255), 0, True, 64, 162),
+        (color565(255, 255, 0), 0, True, 64, 216),
+        (color565(255, 0, 255), 0, True, 64, 270),
+        (color565(255, 0, 0), color565(0, 255, 255), False, 128, 0),
+        (color565(0, 255, 0), color565(255, 0, 255), False, 128, 54),
+        (color565(0, 0, 255), color565(255, 255, 0), False, 128, 108),
+        (color565(255, 255, 255), 0, False, 128, 162),
+        (color565(255, 165, 0), 0, False, 128, 216),
+        (color565(185, 0, 255), 0, False, 128, 270),
+        (color565(255, 0, 0), color565(0, 255, 255), True, 191, 0),
+        (color565(0, 255, 0), color565(255, 0, 255), True, 191, 54),
+        (color565(0, 0, 255), color565(255, 255, 0), True, 191, 108),
+        (color565(255, 255, 255), 0, True, 191, 162),
+        (color565(255, 165, 0), 0, True, 191, 216),
+        (color565(185, 0, 255), 0, True, 191, 270),
+    ]:
+        palette = create_palette(*parameter[:3])
+        placeholder_fb.blit(invader_fb, 0, 0, -1, palette)
+        display.draw_sprite(placeholder, *parameter[3:5], w, h)
+
+    sleep(10)
+
+    display.cleanup()
+
+
+test()